JP3105557B2 - Motor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a motor device which does not have a position detector such as a Hall element which can detect a magnetic pole position of a rotor magnet even when the rotor is stopped.

[0002]

2. Description of the Related Art In a DC brushless motor device, a rotor is rotationally driven by detecting a magnetic pole position of a rotor magnet and commutating an exciting current of a stator coil according to the detected magnetic pole position. I do. In order to detect the magnetic pole position, there are a system using a position detector such as a Hall element and a sensorless system using an electromotive voltage induced in a stator coil by rotation of a rotor.

When a position detector such as a Hall element is used,
Since the magnetic pole polarity of the rotor magnet and its position can be detected even when the rotor is stopped, the motor can be easily started in a predetermined direction by energizing the stator coil according to the detected magnetic pole position. . However, since the positioning accuracy when mounting the position detector greatly affects the torque characteristics and the like, considerable accuracy is required for the positioning, failure due to connection error when mounting the Hall element, etc., and the position detector itself There is room for improvement in terms of manufacturing efficiency and product reliability due to, for example, the occurrence of some defects in the device and the problem of deterioration of the Hall element and the like due to heat.

On the other hand, in the case of sensorless operation, since a position detector is not used, the motor can be made smaller and more efficient, and the positioning of the position detector becomes unnecessary. There is no problem such as a defect of the detector itself and deterioration due to heat. However, when the rotor is stopped, the polarity of the magnetic pole of the rotor magnet and its position cannot be detected. Therefore, in the starting method of the three-phase motor, the stator coil is forcibly excited by a fixed step sequence, and after the rotor starts to rotate and a sufficient electromotive voltage is induced in the stator coil, the magnetic pole position is changed. A method of detecting and rotating is adopted. However, in a two-phase motor such as in an axial fan,
The rotation direction cannot be given as a signal, and the rotation direction cannot be regulated. Further, at the moment of starting, a dead point may occur in the positional relationship between the stator and the rotor.

[0005] In the latter case, in which the stator core is deformed, there arises a problem that efficiency is reduced and vibration is increased.
In addition, in the former case where the start is performed in a fixed step sequence, the start may fail depending on the position of the magnetic pole of the rotor magnet.Therefore, by detecting the non-start and repeating the step sequence, the reliability of the start is increased. Therefore, the problem of circuit complexity and cost increase has been caused.
Therefore, for a relatively inexpensive device such as a fan motor, such means cannot be taken due to cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to provide a Hall element capable of detecting the magnetic pole position of a rotor magnet even when the rotor is stopped. It is an object of the present invention to provide a motor device which can be started easily and surely without using a position detector, and has good characteristics in terms of efficiency and vibration and which can be easily used for automatic assembly at a relatively low cost.

[0007]

In order to achieve the above object, a motor device according to the present invention comprises a rotor having permanent magnet field means, a stator having an armature, and a magnetic field strength of the rotating rotor. And a drive unit for rotationally driving the rotor by commutating the exciting current of the armature coil in accordance with a change in the magnetic field detected by the detection unit. In a two-phase four-pole motor device having no means for detecting a field pole position of a middle rotor, an armature coil is excited so that a pair of adjacent armature magnetic poles have the same polarity. Starting position positioning means for positioning the field poles having the opposite polarity to those of the armature magnetic poles at the intermediate positions of the magnetic poles, and changing the excitation state of the armature coils to change the direction of the synthetic magnetic field, thereby setting the rotor to a predetermined position. In the direction It is intended to comprise a start-up rotation means for moving.

[0008]

When the armature coils are excited by the starting position setting means so that a pair of adjacent armature magnetic poles have the same polarity, the field magnetic poles having the opposite polarity to those of the armature magnetic poles are moved to predetermined positions, that is, the pair of armature magnetic poles. It can be located at an intermediate position between the armature magnetic poles.

By changing the excitation state of the armature coil by the starting rotation means, the direction of the combined magnetic field by the pair of armature magnetic poles can be changed to a predetermined direction. The magnetic pole moves, and the rotor can be reliably started in a predetermined direction.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a main part of a two-phase four-pole half-wave sensor type sensorless motor device as one embodiment of the motor device of the present invention, and FIG. 2 is a block diagram showing an outline of the circuit.

Reference numeral 10 denotes a rotor, 12 denotes a stator,
The rotor 10 is rotatably supported coaxially with the stator 12. Reference numeral 14 denotes a rotor magnet as permanent magnet field means. N in rotor magnet 14
The indication of S indicates the polarity on the side facing the stator 12.

Reference numeral 16 denotes a stator core, and reference numeral 18 denotes a stator coil (armature coil) wound around teeth of the stator core 16, and these constitute a four-pole armature. In the illustrated example, two opposite poles of the excitation polarity of the stator coil 18 are connected to the magnetism. On the other hand, if the rotor magnet 14 has, for example, six poles, the opposed two-pole coil 1
8 is connected to demagnetization.

This motor device has a magnetic pole strength detection circuit 20.
, An energization logic circuit 22, a drive circuit 24, and a start position / start rotation circuit 26. The magnetic pole strength detection circuit 20 is provided with the non-energized stator coil 18.
The counter electromotive voltage induced by the rotation of the rotor magnet 14 is detected and converted into a magnetic pole position signal corresponding to the magnetic pole position of the rotor magnet 14. This magnetic pole position signal is supplied to the energizing logic circuit 22. Since the position is detected by using the stator coil 18, various problems in the case of using a hall element or the like are solved, and high reliability is obtained.

The energization logic circuit 22 performs a logical operation on the order of energization of each stator coil 18 based on the magnetic pole position signal, and supplies an energization signal to the drive circuit 24. The drive circuit 24 has a drive transistor. The drive transistors are alternately turned on and off based on an energizing signal from the energizing logic circuit 22 to supply an exciting current to the stator coil 18.

As a result, the stator coil 18 is excited according to the position of the magnetic pole of the rotor magnet 14, and generates a driving torque. However, since the magnetic pole position of the rotor 10 is detected by the back electromotive voltage induced in the stator coil 18, it cannot be detected when the rotor 10 is stopped.

The start position / start rotation circuit 26 first supplies a signal for exciting the stator coil 18 to the energizing logic circuit 22 so that each of a pair of adjacent armature magnetic poles becomes, for example, the N pole. After a certain period of time in this state using the means, the signal for exciting one of the stator coils 18 is stopped. This fixed time is calculated from the time when the magnetic pole of the rotor magnet 14 moves to the next armature magnetic pole, and is set to a predetermined value.

When the stopped rotor 10 is started up, first, the stator coils 18A, _1B are set so that the pair of adjacent armature magnetic poles 28 and 30 become N poles (N _A , N _B ).
A signal for exciting 8B is supplied to the energizing logic circuit 22 (FIG. 1 (b)). Then, the energization logic circuit 22 outputs a signal for turning on the corresponding drive transistor, and the stator coil 18 is excited so that the armature magnetic poles 28 and 30 become N poles. Thereby, the direction of the magnetic field synthesized by the armature poles 28 and 30 is
As shown in (b), the direction becomes an intermediate direction (φ) between the armature magnetic poles 28 and 30. By keeping a certain time in this state, the rotor magnet 14 is positioned at an intermediate position between the armature magnetic poles 28 and 30. The south pole can be located.

Thereafter, when the signal for exciting one of the stator coils 18A is stopped, the direction of the magnetic field generated by the armature magnetic poles 28 and 30 changes to the direction of (φ _B ) shown in FIG. A torque is generated to rotate the rotor 10 in the direction (clockwise), whereby the rotor 10 is reliably started in a predetermined direction.

In the case where the rotor 10 has a sufficient starting speed by starting in this manner, immediately after starting,
By switching to the above-described driving method based on the back electromotive voltage induced in the stator coil 18, steady rotation can be achieved.

If the starting speed is not sufficient, a signal generating circuit may be provided, and after starting, the signal generating circuit may be operated to repeat the above-described starting rotation. In this case, when the energization logic circuit 22 receives a signal from the signal generation circuit, it supplies an energization signal for exciting the stator coil 18 to the drive transistor of the drive circuit 24 in the order of rotating the rotor 10 in a predetermined direction. Then, after the rotor 10 is accelerated to a predetermined level, the driving system is switched to the above-described driving system based on the back electromotive voltage.

In order to further increase the starting torque,
At the time of starting, for example, means for turning off one of the two stator coils excited so that adjacent armature magnetic poles have the same polarity and flowing a reverse current to the other, or both excited stator coils Or means for backflowing one of them. In the case of accelerating with a repetitive signal, the rising torque can be increased by reversing the direction of the rising current by this signal from the direction of the exciting current at the time of starting.

The sensorless brushless motor device of the two-phase four-pole half-wave conduction type has been mainly described above as an example, but it goes without saying that the present invention is not limited to this.
For example, the present invention can be applied to various motor devices such as a three-phase six-pole full-wave conduction system.

[0023]

According to the motor device of the present invention, after the starting field positioning means positions the predetermined field pole of the rotor at the predetermined position, the starting rotation means changes the resultant vector of the magnetic field to orient the rotor in the predetermined direction. Since the starting can be reliably performed, the starting in the predetermined direction can be easily and surely realized as compared with the case of starting by stepping like a conventional sensorless motor, and the motor rotation speed can be rapidly increased. Can be raised.

Further, compared to the case where the rotor is stopped at a position where torque can be generated by utilizing cogging by the deformed armature core, the vibration is more efficient and the vibration is lower.

Therefore, by eliminating the position detector such as the Hall element which can detect the position of the field magnetic pole even when the rotor is stopped, the positioning step of the position detector can be omitted, the mounting of the position detector can be mistaken, and the position detector itself can be removed. Providing a highly efficient and low-vibration motor device that can be started easily and surely while reducing the problems of defects and deterioration and increasing the production efficiency, and that is relatively inexpensive enough to be used in, for example, a fan motor. can do.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of a sensorless motor device.

FIG. 2 is a block diagram illustrating an outline of a circuit.

[Description of Reference Numerals] 10 rotor 12 stator 14 rotor magnet 18 stator coil 18A stator coil 18B stator coil 28 armature magnetic pole 30 armature magnetic pole

Claims (1)

(57) [Claims] 1. A rotor having permanent magnet field means, a stator having an armature, a detecting means for detecting the strength of a magnetic field of a rotating rotor, and a change in a magnetic field detected by the detecting means. armature by commutating the excitation current of the coil and a drive means for rotationally driving the rotor, two-phase four-pole having no means for detecting the field magnetic pole position of the rotor stopped in accordance with the In the motor device, the armature coil is excited so that a pair of adjacent armature magnetic poles have the same polarity, and a field magnetic pole having a polarity opposite to that of the armature magnetic pole is positioned at an intermediate position between the pair of armature magnetic poles. And a starting rotation means for changing the excitation state of the armature coil to change the direction of the combined magnetic field and start the rotor in a predetermined direction.